Helen Mirren’s bikini fitness secret is a 12-minute workout modeled after the Royal Canadian Air Force exercise plan.

Helen Mirren maintains her fit bikini body at age 70 by doing 12-minute calisthenics workouts modeled after the Royal Canadian Air Force exercise plan.

Mirren’s workout routine incorporates stretching and calisthenics such as push-ups, sit-ups and running in place, as Celebrity Health Fitness has reported.

The Air Force exercise plan was developed by a doctor in the 1950s as a way to help men and women get a total-body workout without gym equipment.

Helen, who made international headlines after showing off her sizzling bikini body in 2008 (at age 62), said the Air Force routine is the only exercise plan she has ever followed.

As for diet, Mirren isn’t a fan of anything extreme, saying she prefers to eat well most of the time without depriving herself. Like many people, Helen has tried lots of different trendy diets, only to lapse after each one.

“I’ve gone through many diets that are also so boring,” she told the Mirror. “You stop eating and that’s what makes you lose weight: not eating. But as you get older, losing weight doesn’t make your body look better. I eat healthily but not that healthily.”

As for her much talked-about 2008 red bikini photo, Helen insists she doesn’t actually look that good, and chalked it up to a flattering angle.

“The truth is I don’t really look that good, it was just a flattering picture,” she said. “I am beyond the bikini-wearing age, really. I wouldn’t normally wear one. I look like a woman in her 60s. I’ve always looked awful in a bikini, even when I was young.”

Super-fit Over-50 Celebrities Redefine Healthy Aging

Mirren joins a growing number of celebrities who are redefining middle age and beyond. Supermodel Elle Macpherson recently showed off her incredible bikini body at 50. Macpherson credited daily exercise and a low-carb alkaline diet for her sleek physique.

Similarly, Christie Brinkley looks unbelievable at age 60, thanks to her longtime vegetarian diet and regular workouts that include yoga, strength-training, running and walking. Like Macpherson, Christie’s anti-aging beauty secrets include careful skincare.

Christie said she has followed a vegetarian diet since age 12. Brinkley said she typically has oatmeal with mixed berries with breakfast, a large salad with beans and nuts for lunch, and pasta with vegetables for dinner.

Brinkley joins a long list of celebrity vegans, including Jared Leto, Al Sharpton and Samuel L. Jackson. They have all credited the plant-based diet for giving them more energy, helping them lose weight, and staying youthful-looking.

The age-defying effects of a vegan diet are no surprise to Dr. David Katz, director of Yale University’s Prevention Research Center. “If you shift to a diet more about plant-based foods, you are likelier to live healthier and experience less chronic disease,” said Katz, author of Disease Proof.

Dr. Joel Fuhrman agrees. “The more greens you eat, the more weight you will lose,” said Dr. Fuhrman, author of The End of Dieting.

Like Macpherson and Mirren, Brinkley hasn’t gone overboard with plastic surgery, and said the secret to aging well is having a positive attitude. “I don’t believe in allowing my age to define me,” she said. “And I really believe attitude plays a huge part in how you feel.”